Students typically study various subjects. For example, students may study the discovery of the Americas by Christopher Columbus in a first year history course, Roman Antiquity in a second year course, and the Industrial Revolution in a third year course. The students may study these subjects without a sense of the greater context of the facts that are the focus of each subject. It is often more useful to know the relationship between facts than to know the facts themselves. For example, it is often more informative to know that Mozart was born before Beethoven than to know the date Mozart was born.